Radioimmunoscintigraphy of ovarian tumours with technetium-99m labelled monoclonal antibody-170: first clinical experiences

The recently developed technetium-99m-labelled monoclonal antibody-170 (MAb-170) was designed for diagnostic use in patients suffering from gynaecological adenocarcinoma. The present investigation was initiated to verify its usefulness for radioimmunoscintigraphy of ovarian tumours. Most of the 30 patients participating in this study underwent immunoscintigraphy prior to first-look surgery. Biokinetic evaluation in two patients showed a plasma half-time of 18.9 h (mean value, n=2, r=0.98) and a biexponential total body curve with values of 7.7 h and 17 days (r=0.98). The mean 24-h urinary excretion was 12% of the injected dose. Radioimmunoscintigraphy using the MAb-170 recognised 12 of 13 cases of adenocarcinoma of the ovaries, corresponding to an overall sensitivity of 92.3%. Specificity was 94.1% (16/17). The calculation of accuracy yielded a figure of 93.3% (28/30). Of 33 known lesions, 26 were visualised successfully; thus the locoregional sensitivity was 78.8%. Of 29 benign tumour sites, 28 showed no evidence of tracer accumulation, corresponding to a locoregional specificity of 96.6%. The smallest lesion visualised was an adenocarcinoma of the corpus uteri with a diameter of 1.5 cm. (orig./UG)